“Dark or gal­lows hu­mour is an in­cred­i­bly good way to cope with a trau­matic sit­u­a­tion be­cause we can’t nor­malise some sit­u­a­tions but we can try to take the in­ten­sity out of them. If we mock them they don’t seem as bad.”

El­liott said Tieche’s joke was one of the few things he re­mem­bered about the day he was shot on pa­trol in south­ern Afghanistan.

“I guess that’s a pretty Aus­tralian thing,” he said.

“The dark hu­mour def­i­nitely helped.”

Marl­bor­ough said dark hu­mour in­cluded things that would seem “grossly in­ap­pro­pri­ate” if taken out of the con­text of the in­tense sit­u­a­tion where it oc­curs.

For­mer com­mando Ma­jor Bram Con­nolly said the prac­tice dated back to Gal­lipoli.

“I re­call sto­ries about guys on the way out of the trench ... walk­ing past and shak­ing the hand of some­one who had been killed,” he said. “Ob­vi­ously that’s not funny, but it prob­a­bly was to them.

“For us it can be a sim­i­lar thing. Once we were pa­trolling ... and a huge ex­plo­sion hap­pened and the Tal­iban started shoot­ing and some­one yelled out ‘awe­some, they’re shoot­ing at us’.